New Common ID for Private Endpoint

[tombuildsstuff]

Private Endpoint is used across the AzureRM Provider, as such when the network service gets updated, the API version specific import needs to change in every place the Private Endpoint Resource ID is referenced, as can be seen in hashicorp/terraform-provider-azurerm#23875

We should make Private Endpoint a Common ID, meaning these imports reference the commonids directory, rather than privateendpoints within a given version of the network service across the Provider - which'll reduce the churn.

Resource ID format: /subscriptions/%s/resourceGroups/%s/providers/Microsoft.Network/privateEndpoints/%s